The invention relates to an electrodynamic transducer head for non-destructive testing of workpieces using ultrasound, having a magnet such as a solenoid with at least two pole shoes, to at least one of which is allocated a probe comprising an exciting and a receiving coil, said probe being covered by a protective plate on the workpiece side, with the transducer head having on the workpiece side a detachable cover such as a cap penetrated by sliding blocks resting on the workpiece.
A transducer head of this type is shown in EP-A-O 168 011. The transducer head shown in DE-C-34 01 072 is of similar design.
DE-A 36 14 069 shows a device for non-destructive testing by ultrasound, in which at least three pole pieces of changing polarity are provided, to each of which is allocated a probe. Each probe can be embedded in a separate cap, which can support a wear protection element if necessary.
The known transducer heads each have a single probe per pole shoe or pole piece, so that a considerable quantity of apparatus is required to arrange several probes next to one another and in addition spaced apart to achieve a high measurement density. As a result, high feed rates for pipes to be checked are almost impossible to achieve to the required extent.
Even if the probe itself is protected by sliding blocks extending over it as in known measuring heads, its replacement or inspection is necessary from time to time. This requires considerable effort, since the probes are firmly installed in the transducer heads.